Extension milling head



Jan. 5, 1965 H. w. SHERMAN EXTENSION MILLING HEAD Filed March 1l, 1963 United States Patent O 3,164,063 EXTENSIN MHJLHNG HEAD Hamid W. Sherman, Inglewood, Calif., assigner to The J. & M. Co., Inglewood, Calif., a corporation of California Fited Mar. 11, 1%3, Ser. No. 264,185 3 Claims. Y (CI. Ni- 17) This invention relates to milling machines and, more particularly, to a novel cutting tool extension arm for a milling machine.

Many times it is desired to perform milling operations inside small cavities of parts. The space in which the milling operation is to be performed may be extremely small in both height and width. Additionally, itjmay be necessary to perform the milling operation in such a cavity right up against a wall of the cavity. A speciiic example of the present invention is an extension device for the cutting tool of a milling machine which is arranged with a special cutting tool support assembly which may be extended into very small cavities of parts for performing7 milling operations. Additionally, the extension device is arranged with a special drive assembly so that milling operations may be performed immediately adjacent the side or" a wall of a small cavity or even right in a corner of the cavity. The extension device embodying the present invention is extremely small but yet is rigid and has a special preloaded bearing arrangement which prevents chatter in the extension device even under severe loads during milling operations. Additionally, the extension device is arranged so that the distance between the axis of the cutter support shaft and the end of the extension arm is minimized. Further, the adapter, the extension member and the coupling device between the mill spindle and the tool support assembly is arranged for quick mounting and dismounting from the milling machine.

A specific embodiment of the present invention is an extension milling head for a milling machine having a drive spindle and milling machine housing, the combination comprising: cutting tool support shaft means; support means rigidly coupled to the milling machine housing including a rigid and elongated extension thereof having an end extending out spatially from the spindle of such milling machine and bearing means arranged for rotatably mounting said shaft substantially adjacent the spatial end of said extension; and 'continuous drive means adapted for coupling the shaft means to the spindle of such milling machine.

These and other aspects of the present invention may be more fully understood with reference to the following description of the drawings of which:

FIG. 1 is a pictorial View of a cutting tool extension device mounted on the housing of a milling machine and embodying the present invention;

FIG. 2 is a side elevation view of the extension member, the tool support assembly and a portion of the connecting bolt with a portion of the member and tool support assembly cut away along the line 2-2 shown in FIG. l with the cutting tool of FIG. 1 removed; and

FIG. 3 is a top elevation view or" a portion of the extension member along the line 3 3 of FIG. 2 with the connecting bolt therein.

Refer now to the present invention. FIG. 1 is a picv The adapter also has a cut extending inV from the rear of the adapter into the circular opening v ICC and arranged whereby a bolt Mb, extending through the slit 14C and threaded into the adapter 14, may be tightened and pull the sides of the opening into the tight frictional engagement with the housing 12a. The elongated and rigid member or extension member 10 is connected to the adapter 14 by means of a bolt 14d (shown in dashed lines in FIG. 1) and extends out perpendicular to a plane through the axis of the spindle shaft 16 of the milling machine 12.

Referring now to FIGS. l and 2, one end of the extension member 10 is positioned out spatially from the spindle shaft 16 and contains a cutting tool support assembly The cutting tool support assembly 20 has a cutting tool support shaft 20a to which various mill cutting tools such as 20j may be mounted.

Referring in particular to FIG. 2 wherein the cutting tool support shaft Zita is shown in section with the cutting tool 26j removed, it will be noted that a V-shaped groove Ztl/1 is provided around the outer diameter of the cutting tool support shaft 2da into which set screws may extended for tightly securing cutting tools.

The cutting tool support shaft 20a has two different diameters providing a shoulder on the shaft. A pair of matched bearings Ztlb and 20c are provided and are securely mounted to the shaft by press-fitting the inner races of the bearings to the shaft Zilla. The matched bearings 2017 and 20c are angular contact single row ball bearings and, when manufactured, are machined for a preloaded condition. The bearings are arranged for handling both thrust and radial loads during milling operations.

The extension member 10 has two cavities formed ad'- jacent the end which mounts the cutting tool support assembly 2d. The lirst cavity Zilk extends through the extension member 1@ vertically and parallel with the axis of the shaft 20a, The second cavity Ztlm extends in from the end of the member 16 parallel with the length of the extension member 10 and in between the matched bearings 2tb and 20c. The cavity 20k is arranged forming a recess or bearing housing on the top and bottom of the member'ltl for securely mounting the bearings Ztlb and Zilc with the outer races of the bearings secured so that no radial movement will be caused due to 'loading during milling operations. The cavity 29k is arranged so that the bottom of the recesses are defined by shoulders in the member 10 on which the outer races of the matched bearings Zibb and 20c rest.

A coupling device or timing belt pulley Ziis is securely mounted to the cutting tool support shaft 2da by means of a set screw Zhu. The timing belt pulley Ztls is positioned and arranged within the cavity 26m for rree rotation.

A pair of spacers 2li@ and 2M are positioned in between the timing belt pulley 26s and the matched bearings Zb and 20c. The spacers Ztb and Ztlc are dimensioned so that only the inner and not the outer races of the bearings 2Gb and Ztlc restrthereon. A cap 2tlg is connected to the shaft by means of screws 20p and extends over the inner races of the top bearings 29C.

The length of the cutting tool support shaft 20a in between the shoulder and the opposite end thereof, the vwidth of the spacers Ztle and Ztlf and the width of the timing belt pulley Ztls are dimensioned such that when the cap 2tlg is securely tightened down to the end of the cutting tool support shaft 26a, the inner races of the bearings Zlib and 26e are forced toward each other with theproper preload to avoid chatter and axial movement of thefshaft 29a parallel with its axis caused by loading during milling operations. The proper preload is obtained kby dimensioning the' widths of the spacers 20e and Ztlf Vand the Width of the pulley Ztls such that the distance between the inner races of the bearings 2Gb and 20c is slightly less than the leferencel letter:

distance between the outer races of the bearings Zlib and 2de, determined by Ithe dimension' between the shoulders in the cavity Zlk supporting the outer races of the bearings 2Gb and Zllc. v

A pair of support Vrings Zhi are connected to the member l@ by means of screwsA Ztlr threaded into the member li). lThe supporting ringsil extend over the outer races of the bearings 2Gb and Zic and tightly secure the outer races into the bearing housing of the member lil.

The matched bearings 2Gb and Zlicare of the type manufactured by the Marlin Rockwell Corporation yand identified as single row duplex radial type R, an angular type bearing having Model No. MRC 7l0lKRD.

yA continuous drive means or timing beltv 18 is provided for coupling the timingbelt pulley Zes 4to a timing belt pulley 17 connected to the spindle of the milling Vas possible and yet lallow the timing belt ld to remain vinside of the end of the extension member ld. In this manner, the extension member lll can be moved with a cutting tool connected to the shaft 2do as close as possible to the side of a part being milled without obstruction by the belt 18er the end material of the member ld.

The portion of the extension member l@ `connected to the adapter 14 contains an elongated cavity lltlb through which the bolt 14d is extended and threaded into the 4adapter lid. The elongated cavity llb of the extension member lil is arranged with a smaller diameter adjacent the adapter 14 to provide a shoulder against which the head of the bolt may be tightened for forcing the extension member 1d into tight engagement with the adapter 14.

The cavity Mib is elongated so that the extension member 10 can be moved in and out perpendicular to the axis of the spindle 16 and thereby adjust for the correct tension on the timing belt 1S. l.

The adapter le contains a grooveldej (indicated by dashed lines) into which the end of the extension member 10 which engages the adapter le fits. The groove 1de is arranged so that it provides a tight lit for the extension member ld and prevents rotational movement of the extension member lll) in the radapter lll.

ln a preferred embodiment of the invention for milling aluminum castings, the extension member lil is No. lO-lS steel and the adapter 1d is aluminum.

Although a preferred embodiment of the invention has been shown and described herein, it should be understood that other extension milling devices may be devised within `the scope of the present invention. For example, although a ltiming belt i8 is preferred, a chain drive may be used along with sprockets in place of the timing belt pulleys. Also, other continuous ldriving devices may be fused for coupling the spindle and thecutting tool support shaft together. Also, it may be desiredl to form an angle in the extension member l@ so that the cutting tool may Y be moved into hard to reach locations of parts being milled. y

Listed below are the'dimensions indicated by the reference letters shown in FfG. 2 of a preferred extenassembly.

Dimension,

What is claimed is:

l. An extension milling head for a milling machine having a drive spindle with a connected drive pulley and a spindle housing lsurrouding the spindle, the combination comprising:

a cutting tool assembly comprising a cutting tool support shaft, a pulley mounted to said shaft for rotation thereof, and a bearinfy positioned on both sides of said pulley for rotatably mounting said shaft; a rigid and elongated mounting member including bearing housing for each bearing for mounting the bearings at substantially a iirst end of the member, the bearing housings including a portion having a smaller diameter in between the faces of the mounted bearings for rotatably mounting said shaft and preventing motion of the shaft in the member parallel with the axis of the shaft and a recess extending parallel with the length and in between sides of the elongated member for allowing free rotation of the cutting shaft pulley and to allow a drive belt to be coupled to the pulley and move clear of the first end of the member; an adapter arranged for rigidly connecting the member at substantially a second end thereof to a milling machine spindle housing With the first end of the member projecting outwardly from and perpendicular to a plane tnrough the axis of such milling machine spindle; and a drive belt arranged for coupling the rota-tion of a drive pulley connected to the milling machine spindle to the cuting shaft pulley.

2. An extension milling head for a milling machine having a drive spindle with a connected drive pulley and a spindle housing surrounding the spindle, the combination comprising:

a rigid and elongated mounting member comprising a circular cavity extending therethrough adjacent a iirst end thereof, a pair of circular recesses for mounting bearings positioned on opposite sides of the member concentric with the cavity and a groove extending in from the first end of the member past the cavity and in between said recesses; a cutting tool assembly comprising a tool support shaft arranged extending out of at least one end of the cavity, a pair of bearings mounted in said recesses and arranged for rotatably mounting said shaft, and a timing belt pulley mounted on said shaft and positioned yin said groove with the edge thereof short of the end of the member for rotating the shaft, said cutting tool assembly being arranged with the bearings preloaded and arranged in cooperation with said member for preventing axial movement of said shaft; an adapter arranged for rigidly connecting said member at substantially a second end thereof to a milling machine spindle housing with the first end of said member extending outwardly from and perpendicular to a plane through the axis of such milling machine spindle; and a timing drive belt arranged for coupling the shaft pulley to a timing drive pulley connected to the milling machine spindle.

3. An extension milling head for a milling machine having a drive spindle with a connected drive pulley and a spindle housing surrounding the spindle, the combination comprising:

a rigid and elongated mounting member comprising a circular cavity extending therethrough adjacent a rst end thereof, a pair of circular recesses for mounting bearings positioned on opposite sides of the member concentric with the cavity and a groove extending in from the rst end of the nrember past the cavity and in between said recesses; a cutting tool assembly comprising a tool support shaft arranged extending out of at least one end of the cavity; a pair of bearings mounted inY said recesses and arranged for rotatably mounting said shaft, and a pulley mounted on said said shaft and positioned in said groove for rotating the shaft, said cutting tool assembly being arranged with the bearings preloaded and arranged in cooperation with saidmember for preventing axial movement of said shaft; an adapter arranged for rigidly coupling said member at substantially a second end thereof to a milling machine spindle housing with the irst end of said member extending outwardly from and perpendicular to the axis of such milling machine spindle, said member including an elongated cavity adapted to receive a connecting member for connecting the adapter to the member and allow adjustment of -t-l'ie member perpendicular to `the spindle shaft; and a drive belt arranged for coupling the shaft pulley to a drive pulley connected to the milling machine spindle.

References Cited in the le of this patent UNITED STATES PATENTS 229,115 Forbush ct al. June 22, 1880 1,627,934 Stein May l0, 1927 2,286,931 Radeke June 16, 1942 2,364,328 Thorsberg Dec. 5, 1944 2,519,206 Van Ausdall Aug. 15, 1950 2,669,162 Arliss Aug. 15, 1954 2,718,820 Fasclt Sept. 27, 1955 v FOREIGN PATENTS 841,243 Germany Iune 13, 1952 

1. AN EXTENSION MILLING HEAD FOR A MILLING MACHINE HAVING A DRIVE SPINDLE WITH A CONNECTED DRIVE PULLEY AND A SPINDLE HOUSING SURROUNDING THE SPINDLE, THE COMBINATION COMPRISING: A CUTTING TOOL ASSEMBLY COMPRISING A CUTTING TOOL SUPPORT SHAFT, A PULLEY MOUNTED TO SAID SHAFT FOR ROTATION THEREOF, AND A BEARING POSITIONED ON BOTH SIDES OF SAID PULLEY FOR ROTATABLY MOUNTING SAID SHAFT; A RIGID AND ELONGATED MOUNTING MEMBER INCLUDING BEARING HOUSING FOR EACH BEARING FOR MOUNTING THE BEARINGS AT SUBSTANTIALLY A FIRST END OF THE MEMBER, THE BEARING HOUSINGS INCLUDING A PORTION HAVING A SMALLER DIAMETER IN BETWEEN THE FACES OF THE MOUNTED BEARINGS FOR ROTATABLY MOUNTING SAID SHAFT AND PREVENTING MOTION OF THE SHAFT IN THE MEMBER PARALLEL WITH THE AXIS OF THE SHAFT AND A RECESS EXTENDING PARALLEL WITH THE LENGTH AND IN BETWEEN SIDES OF THE ELONGATED MEMBER FOR ALLOWING FREE ROTATION OF THE CUTTING SHAFT PULLEY AND TO ALLOW A DRIVE BELT TO BE 